Larval drift of amphidromous shrimp and gobies on the island of Oahu, Hawai‘i

Luton, C.D., A.M.D. Brasher, D.C. Durkin & P. Little.

As is typical of aquatic macrofauna on tropical and subtropical montane islands, Hawaii’s native stream fauna exhibit a migratory life cycle. In this life cycle, called amphidromy, newly hatched fish and shrimp larvae drift downstream to the ocean, recruit back to stream mouths as juveniles, and then migrate upstream to live as adults. On Oahu, urbanization has led to widespread habitat degradation, especially in lower stream reaches, that can potentially disrupt the amphidromous life cycle of the native stream fauna. In this study, we collected drifting larvae from 19 sites in 8 streams on the island of Oahu to examine larval presence/absence and distribution. In addition, in one watershed (Manoa-Palolo) we compared composition and abundance of drifting larvae to that of adult populations. The most frequently collected larval species were those that, as adults, are tolerant of a wider range of environmental conditions. Degraded streams produced the fewest drifting fish larvae, and the least altered stream produced the most. Abundances of larval species did not correlate with abundances of adults. As a management strategy, drift sampling may be most useful when used in conjunction with other monitoring methods, such as surveys of adult populations or monitoring returning post-larvae.

Karst on Guam is found in two distinct physiographic provinces. The northern half of the island is an uplifted karst plateau formed on Pliocene-Pleistocene reef-lagoon deposits. In the south, the karst is confined mostly to Miocene remnants on uplifted weathered volcanic terrain; except on the southeastern coast, where it has developed in former fringing reef limestone contemporaneous with the limestone of the north. Across these environments, the karst of Guam is remarkably diverse—exhibiting not only island karst features, but also continental karst features generally associated with ancient, diagenetically mature limestones. Features are mapped and described in this paper in terms of five categories reflecting the sequence of water movement, namely (1) surface catchment features, (2) surface flow features, (3) closed depressions, (4) caves, and (5) discharge features.

Surface catchment features include karren and the epikarst, artificial ponding basins, storm water injection wells, etc. Surface flow features include streams originating on allogenic and autogenic catchments, insurgences, dry valleys, valley sinkholes, and contact and resurgence springs. Most closed depressions on the island are of primary depositional origin, but there are also numerous true sinkholes of solutional and collapse origin. Caves on Guam include pit caves at the surface, stream caves along bedrock-basement contacts, and water table, halocline, and flank margin caves, which are all hypogenic and associated with present and past positions of the fresh water lens. The vast majority of discharge features are located along the coast. They include beach springs and seeps, reef springs and seeps, flowing fractures and caves, and submarine springs, and their distribution and density reflect the relative areas and shape of the catchments feeding them. A few high-level springs can be found in the interior, mostly rising at carbonate-non carbonate contacts.

Distribution, Abundance and Management of Potential Commercial Holothurians in Pohnpei Lagoon, Federated States of Micronesia

Bourgoin, A. & A. Edward.

From May 28 to June 5, 2004, sixty-three 400-m2 stations were surveyed throughout the five municipality lagoon waters of Pohnpei Island to evaluate the densities and distribution of potential commercial holothurians. Thirty-eight per cent of the stations were concentrated on the barrier-reef crest, 36.5%, on the back barrier reef platform, and 25.5% within the patch reefs/seaward portion of the fringing reef flat complex. A total of 12,806 individuals represented by six species were registered, equivalent to a mean density of 0.51 ind.m–2. Holothuria atra composed 87.1% of the total number, followed by Stichopus chloronotus, with 5.0%, Actinopyga mauritiana, 4.5%, Holothuria edulis, 2.9%, Bohadschia sp., 0.4%, and Holothuria whitmaei, 0.1%, respectively. By municipalities, all species confound, Uh recorded the highest densities with 0.83 ind.m–2, the lowest being Sokehs with 0.18 ind.m–2. By physiographic zone, a contagious distribution is observed, H. edulis being concentrated within the fringing/patch reef complex, while A. mauritiana occurs mainly on the barrier-reef crest, most frequently at Nett, constituting 25.6% of the 1,958 individuals surveyed there. S. chloronotus and H. atra have representatives in all three defined physiographic zones. The estimated standing crops are 15,000 mt for H. atra, a little over 900 mt for H. edulis, 339 mt and 244 mt, respectively, for S. chloronotus and A. mauritiana. Comparison between annual harvest potential, market prices and mean exploitable age permits one to estimate the gross revenue of a given species. Due to forecasted high annual harvest volumes, H. atra offers the best commercial potential. S. chloronotus and A. mauritiana, are commercially attractive mainly because of their relatively high commercial value. Management strategies are suggested and should be adopted before any commercial holothurian fishery is implemented.

On The Periphery? Archaeological Investigations At Ngelong, Angaur Island, Palau

Clark, G. & D. Wright.

Ngelong is an extensive late-prehistoric site situated within the rugged limestone terrain of Angaur Island. Earlier research documented extensive midden and artefact deposits, but only a few stone structures. Recent archaeological work has confirmed the relative absence of built stone features, and obtained new data—including radiocarbon dates and X-Ray Fluorescence results—to evaluate the Ngelong occupation. These indicate the site dates to 450–250 cal. B.P., and overlaps in time with Rock Island villages containing abundant stone work. Compared to several other prehistoric sites in southern Palau, Ngelong is atypical, and appears to represent community occupation of a peripheral socio-economic landscape as a result of warfare, a possibility also found in traditional accounts. While constructed defences indicate the existence of inter-group hostility in the past, it is suggested the outcome of warfare resulted in significant differences between late-prehistoric Palauan communities, which can be identified in the archaeological settlement record.

On Guam, few archaeological sites with possible agricultural features have been described and little is known about prehistoric cultivation practices. New information about possible upland planting techniques during the Latte Phase (c. A.D. 1000–1521) of Guam’s Prehistoric Period, which began c. 3,500 years ago, is presented here. Site M201, located in the Manenggon Hills area of Guam’s interior, contained three pit features, two that yielded large pieces of coconut shell, bits of introduced calcareous rock, and several large thorns from the roots of yam (Dioscorea) plants. A sample of the coconut shell recovered from one of the pits yielded a calibrated (2 sigma) radiocarbon date with a range of A.D. 986–1210, indicating that the pits were dug during the early Latte Phase. Archaeological evidence and historic literature relating to planting, harvesting, and cooking of roots and tubers on Guam suggest that some of the planting methods used in historic to recent times had been used at Site M201 near the beginning of the Latte Phase, about 1000 years ago. I argue that Site M201 was situated within an inland root/tuber agricultural zone.

7.Randall, J.E. & P. Bartsch.
2005.
Two new soleid fishes of the genus Aseraggodes from Micronesia, with a record of A. smithi from Palau.
Micronesica.
38(1):
125-139.
Date Revised/Accepted: 30 March 2005.

Two new soleid fishes of the genus Aseraggodes from Micronesia, with a record of A. smithi from Palau

Randall, J.E. & P. Bartsch.

The soleid fish Aseraggodes heraldi, formerly identified as A. melanostictus (Peters), is described as a new species from two specimens, 38.5 and 47 mm SL, collected from shallow water at Kwajalein Atoll, Marshall Islands. It is distinct in having 75 dorsal rays, 57–58 anal rays (the rays of both fins branched), 68–70 lateral-line scales, 37 vertebrae, 12 dorsal pterygiophores anterior to fourth neural spine, and no caudal peduncle. A photograph and an x-ray are provided of the holotype of A. melanostictus, known from one specimen taken in 73 m at the island of Bougainville. Aseraggodes firmisquamis is described from one 31.8-mm specimen from 6 m in Palau, distinct in having 66 dorsal rays, 49 anal rays, partially embedded scales, 74 lateral-line scales, 36 vertebrae, 12 dorsal pterygiophores before the fourth neural spine, no caudal peduncle, and a color pattern of many large irregular white spots and three rows of black spots. Aseraggodes smithi Woods, previously known from one specimen, 18.5 mm SL, from Rongerik Atoll, Marshall Islands, is reported from three specimens, 14.5–23 mm SL from 6–10 m in Palau. It is distinguished by having 64–67 dorsal rays, 42–43 anal rays, 64–67 lateral-line scales, a ventral branch of lateral line on head following edge of preopercle; 33–34 vertebrae, 14–15 dorsal pterygiophores before the fourth neural spine, a very short caudal peduncle, a very narrow interorbital space, and light gray color dominated by large irregular dark-edged white spots and a few smaller black spots.

This paper lists a total of 279 bird and 44 mammal species from Micronesia through March 2005, with listings provided for nine island groups or islands, including Palau, Yap, Guam, the Commonwealth of the Northern Mariana Islands, Chuuk, Pohnpei, Kosrae, the Marshall Islands, and Wake Atoll. The region’s avifauna currently comprises 167 visiting species, 81 native breeding species, 13 introduced breeding species, four extinct species, one species extinct in the wild, and 13 hypothetical species. Its mammal fauna contains 18 visiting species, eight native breeding species, 14 introduced breeding species, two extinct species, and two hypothetical species. Species counts are highest for birds at Palau (148 species), the CNMI (144), and Guam (128), and for mammals at Guam (25), Palau (19), and the CNMI (19). These numbers reflect both the closer proximity of these islands to eastern Asia, New Guinea, and the East Asian-Australasian Flyway, and the greater number of observers present. Thirty-eight new bird species have been reported for Micronesia since the last region-wide checklist was published in 1985, whereas the mammal list is the first ever compiled for the region. Species entries in the checklist are annotated with information on status and a documenting reference that is often the first published record. Additional background information on occurrence or taxonomy is given for some species.

Foraging behavior, substrate preference and influence of Echinometra sp. A on the carbonate budget of Nukubuco Reef, Fiji Islands

Appana S.D.A. & V.C. Vuki.

Bioerosion can be important to the configuration and destruction of coral reefs. Echinoids as grazers and burrowers can contribute significantly to coral reef destruction. The rock-boring sea urchin, Echinometra sp. A has colonized extensive areas of dead coral on the Nukubuco reef, Fiji. This study provides data on rates of bioerosion of the reef structure using gut analysis and how these rates vary among size classes of Echinometra. It also provides information on the distribution and behavior of different size classes of Echinometra. This is pertinent to Micronesia and the rest of the tropical Pacific because Echinometra is usually the most prevalent species on the coral reefs. Field sampling on size-specific behavior showed small and medium urchin dominance on the crests engaged chiefly in burrowing and feeding behavior while the flats demonstrated urchins from all representative size classes engaged in feeding, burrowing and scouring. This difference was a reflection of difference in environments. Echinometra sp. A showed a preference for coral rock due to the brittle framework it provides to make burrows and due to the availability of turf algae infested on the dead coral for food. In feeding on algae, it also removes a large portion of coral (CaCO3) substrate. Bioerosion rate was lower on the Nukubuco flats 0.20 x 10–3 kg CaCO3 /urchin/d, compared to the crests, 0.39 x 10–3 kg CaCO3 /urchin/d. These rates compare closely with studies done on the turnover of gut contents by the two major burrowing echinoids on Enewetak Atoll (Echinometramathaei and Echinostrephusaciculatus).

The 40 species of marine benthic algae represent specimens collected on eight occasions between December 1841 and June 1998 from isolated Wake Atoll located 546 km north of the nearest land mass, i.e., Taongi Atoll in the Marshall Islands. Thirty five of the 40 species are reported for the first time from Wake Atoll. The annotated listing includes 5 species of blue-green algae (cyanobacteria), 11 species of green algae, 11 species of brown algae and 13 species of red algae. The marine algae from Wake Atoll are, for the most part, species common to both the Hawaiian Islands and Micronesia, but show a slightly closer affinity with algae from Hawaiian waters. Only the green algae Caulerpa urvilleana and Halimeda renschii, and the brown alga Padina minor have not been reported from the Hawaiian Islands.

11.VanderWerf, E.A.
2006.
Observations on the birds of Kwajalein Atoll, including six new species records for the Marshall Islands.
Micronesica.
38(2):
221-237.
Date Revised/Accepted: 08 November 2005.

Observations on the birds of Kwajalein Atoll, including six new species records for the Marshall Islands

VanderWerf, E.A.

Kwajalein is the largest atoll in the world and is located in the western chain of the Marshall Islands. As part of a team of biologists from the U.S. Fish and Wildlife Service, I conducted bird surveys from 7–20 October 2004 on seven islets in Kwajalein Atoll that are leased by the U.S. Army. This proved to be exceptionally rich period for migratory birds on Kwajalein. I observed a total of 36 bird species, including 6 species not previously recorded in the Marshall Islands (Common Ringed Plover Charadrius hiaticula, Semipalmated Plover Charadrius semipalmatus, Common Greenshank Tringa nebularia, Red Knot Calidris canutus, Long-Billed Dowitcher Limnodromus scolopaceus, and Common Snipe Gallinago gallinago) and 4 species recorded only once before (Marsh Sandpiper Tringa stagnatilis, Red-necked Stint Calidris ruficollis, Curlew Sandpiper Calidris ferruginea, and White-winged Tern Chlidonias leucopterus). Many of the observations were documented with photographs. The water catchments, irrigated and fertilized lawns, and open fields on Kwajalein Atoll may attract migratory birds, or at least cause them to linger, making their detection more likely. Only 4 seabird species were documented or suspected to breed on the islets surveyed. Eradication of alien predators would greatly enhance the suitability of Army-leased islets as nesting sites for seabirds.

An unusual encounter with a mixed school of melon-headed whales (Peponocephala electra) and rough-toothed dolphins (Steno bredanensis) at Rota, Northern Mariana Islan

Jefferson, T.A., D. Fertl, M. Michael & T.D. Fagin.

Little information is available on marine mammals occurring in the Northern Mariana Islands. On 4 July 2004, a group of about 500-700 melon-headed whales (Peponocephala electra) was observed and photographed at the surface and extensively underwater for several hours at the island of Rota in the Northern Mariana Islands. An unidentified number of rough-toothed dolphins (Steno bredanensis) also were part of this sighting. Bottom depths ranged from about 77 to 1,100 m over the course of the sighting.

Five pairs of Little Terns (Sterna albifrons) attempted to nest on Saipan, Commonwealth of the Northern Mariana Islands (CNMI) in May and June 1997. Nesting was observed again in 2002–2005. No young were recorded for either period. The only other recorded attempts were in 1988 and 1989. Two damaged eggs collected in 1997 had traces of contaminants 4-4'-DDE and PCB 1260, but at levels well below what is believed to affect reproductive success. We hypothesize that poor choice of nesting substrate due to limited nesting habitat was a limiting factor in the failure of all nesting. We designed and tested modifications that may help future nesting attempts to succeed.

Extinctions and extirpations in Marshall Islands avifauna since European contact–a review of historic evidence

Spennenmann, D.H.R.

The Pacific Island avifauna underwent dramatic changes fol- lowing the arrival of humans on the islands making several species and genera extinct. The decline continued after the arrival of the Europeans. Drawing on historic sources, this paper describes the local extinction of five bird species (Gallirallus wakensis, Poliolimnas cinereus, Ptilinopus porphyracaeus hernsheimi, Ducula oceanica ratakensis and Acrocephalus rehsei) on the atolls of the Marshall Islands since European contact. The local extinction was largely due to the influences of European traders and planters, as well as a European-style copra economy, creating increased capabilities and demand for local hunting of land birds; changes to the ecosystems such as the clearance of swamps and taro patches to make way for coconut plantations, the intro- duction of predators by European traders and planters; and, on Wake Island, the actions of Japanese feather collectors and changes during World War II.

Icerya imperatae Rao (Hemiptera: Coccoidea: Margarodidae: Iceryini) is reported as a new pest in the Republic of Palau where it has caused serious damage to grasses used for erosion control. The only previous published record of this scale insect is from the Philippines but here we also document it for the first time on various species of Poaceae in Australia, Brunei and Malaysia. We also discuss the distribution and pest status of five other species of Iceryini recorded from the Pacific region. These are Icerya aegyptiaca (Douglas), I. purchasi Maskell, I. seychellarum (Westwood), Crypticerya jacobsoni (Green) and Steatococcus samaraius Morrison.